1. Field of the Invention
This invention relates generally to form work for concrete walls, and more particularly to form construction for curved walls such as for tanks or the like.
2. Description of the Prior Art
There are several patents of which I am aware and which pertain to form work for curved surfaces, and particularly to adjustable forms for that purpose. Examples are U.S. Patents as follows:
______________________________________ U.S. Pat. No. Inventor Date Issued ______________________________________ 869,036 Wood 10/22/07 3,871,612 Weaver 3/18/75 4,185,805 Ewing 1/29/80 4,553,729 Connors 11/19/85 4,619,433 Maier 10/28/86 4,729,541 Maier 3/08/88 4,742,985 Mathis 5/10/88 4,874,150 Heinzle 10/17/89 ______________________________________
Some of the apparatus disclosed in these patents for constructing forms for curved walls is specially made construction which is either not generally and readily available or is fairly complicated and involves considerable work to assemble it, and susceptible to damage or deterioration in use. Examples are shown in the Wood, Maier '433, Maier '541, Mathis, and Ewing patents. The Weaver patent appears to rely on wires to hold interfitting form or mold boards together.
In the Heinzle patent, the form work boards 12 must be dismounted when the curvature of the stretchers 5 is changed.
The Connors patent uses combinations of "mini-walers" and vertically extending "strongbacks" to provide a substantially curved form wall.
The present invention is directed to providing convenient means for on-site assembly of forms which are comparatively light in weight, durable in nature, and reliable in use.